Convolutional Neural Networks (CNNs) [1]} has been successfully used in image classification [2]} and it provides significant improvements in various applications than traditional methods.
It has also been applied for document binarization [3]}, [4]}.
Since the output of binarization has the same size of the input image, the famous frameworks of neural networks are often used, such as the fully convolutional neural networks (FCNs) [5]}, [6]}, holistically-nested edge detector (HED) [7]}, [4]} and U-Net [9]}.
Using deep learning provides a large margin of performance gain compared to traditional methods because millions of parameters in neural networks have been learned on a large training data set.
